KR20190078810A - Electroluminescent Display Device - Google Patents

Abstract

The present invention relates to an electroluminescent display device. The electroluminescent display device according to the present invention includes a display panel in which a display region and a non-display region are defined, wherein the display region has a light emitting region and a non-light emitting region, a cover substrate on the display panel, and an external light blocking layer between the cover substrate and the display panel. The external light blocking layer includes a first layer having a first refractive index and a second layer having a second refractive index smaller than the first refractive index. The external light blocking layer has first and second patterns implemented by the interface of the first and second layers. The first pattern corresponds to the light emitting region, and the second pattern corresponds to the non-light emitting region. Accordingly, the luminance of the electroluminescent display device can be improved by effectively blocking external light while increasing the efficiency of light outputted from light emitting diodes.

Description

[0001] Electroluminescent Display Device [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electroluminescence display device, and more particularly, to an electroluminescence display device capable of preventing reflection of external light.

2. Description of the Related Art Flat panel displays having excellent characteristics such as thinning, lightening, and low power consumption have been widely developed and applied to various fields.

Among flat panel display devices, an electroluminescent display device is a device which injects electric charge into a light emitting layer formed between a cathode which is an electron injection electrode and a cathode which is a hole injection electrode, and pairs electrons and holes and then extinguishes and emits light . The electroluminescent display device can be formed on a flexible substrate such as a plastic substrate. Since the self-emission type display device has a large contrast ratio and response time of several microseconds, It is easy, there is no limitation of viewing angle.

The electroluminescent display device can be divided into a passive matrix type and an active matrix type according to a driving method. An active type electroluminescent display device capable of low power consumption, high definition, and large size is widely used in various display devices have.

However, the electroluminescent display device has a strong reflection of external light, and the brightness of the black state is increased by reflection of external light. As a result, the contrast ratio is lowered and the image quality is deteriorated. Therefore, a structure for blocking external light reflection has been proposed.

1 is a cross-sectional view schematically showing a conventional electroluminescent display device.

1, a conventional electroluminescent display device includes a display panel 10, a phase retardation film 20 positioned on the upper portion of the display panel 10, And a polarizing film (30).

The display panel 10 is a light emitting diode panel and includes a first electrode 14 on a substrate 12 and a light emitting diode De composed of a light emitting layer 16 and a second electrode 18.

The phase retardation film 20 on the display panel 10 has a phase retardation of? / 4 and changes the polarization state of incident light by 90 degrees. Therefore, the linearly polarized light having passed through the phase retardation film 20 is changed into the circularly polarized light, and the circularly polarized light having passed through the retardation film 20 is changed into the linearly polarized light.

 The polarizing film 30 on the phase retardation film 20 is an absorption type polarizing plate that absorbs linearly polarized light parallel to the absorption axis of the polarizing film 30 and transmits linearly polarized light perpendicular to the absorption axis.

The linearly polarized light that is parallel to the absorption axis of the polarizing film 30 in the external light is absorbed by the polarizing film 30 and the linearly polarized light in the external light perpendicular to the absorption axis of the polarizing film 30 is transmitted through the polarizing film 30 do. The linearly polarized light transmitted through the polarizing film 30 is converted into circularly polarized light while passing through the phase retardation film 20 and is converted into circularly polarized light by the first electrode 14 of the display panel 10, The polarized light is converted into circularly polarized light in the opposite direction and is again converted into linearly polarized light passing through the phase retardation film 20 and parallel to the absorption axis of the polarizing film 30 to reach the polarizing film 30, do.

As described above, the conventional electroluminescent display device can prevent the reflection of external light by the retardation film 20 and the polarizing film 30. [

However, the phase retardation film 20 and the polarizing film 30 are expensive and increase the cost of the electroluminescent display device. Since the phase retardation film 20 and the polarizing film 30 are manufactured and attached to the display panel 10 through a plurality of lamination processes, the cost of the electroluminescence display device .

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to solve the external light reflection of an electroluminescence display device.

The present invention also aims to reduce the manufacturing cost of an electroluminescent display device.

According to an aspect of the present invention, there is provided an electroluminescent display device including a display panel having a display region and a non-display region defined therein and having a light emitting region and a non-light emitting region in the display region, Wherein the external light shielding layer comprises a first layer having a first refractive index and a second layer having a second refractive index smaller than the first refractive index, And the first and second patterns formed by the interface of the second layer, wherein the first pattern corresponds to the light emitting region and the second pattern corresponds to the non-light emitting region.

The first pattern may have a curvature at a vertex, and the second pattern may have a vertex at a vertex.

As described above, according to the present invention, the external light blocking layer can be formed on one surface of the cover substrate to prevent the external light from being reflected and output from the display panel.

Accordingly, the contrast ratio of the electroluminescence display device can be increased to improve the image quality.

Further, the electroluminescent display device of the present invention can reduce the lamination process, simplify the manufacturing process, and reduce the cost.

In addition, since the external light blocking layer has different patterns corresponding to the light emitting region and the non-light emitting region, the efficiency of light output from the light emitting diode can be increased while effectively blocking external light, thereby improving the brightness of the electroluminescence display.

1 is a cross-sectional view schematically showing a conventional electroluminescent display device.
2 is a schematic cross-sectional view of an electroluminescent display device according to an embodiment of the present invention.
3 is a circuit diagram showing one pixel region of a display panel according to an embodiment of the present invention.
4 is a cross-sectional view of an electroluminescent display device according to an embodiment of the present invention.
5 is a cross-sectional view of an external light blocking layer according to an embodiment of the present invention.
6 is a view schematically showing a path of external light to the external light shielding layer of the present invention.
7 is a view schematically showing a path of internal light to the external light shielding layer of the present invention.
8 is a plan view schematically illustrating a pixel structure of an electroluminescent display device according to an embodiment of the present invention.
9 is a cross-sectional view schematically showing another example of the first pattern of the external light blocking layer according to the embodiment of the present invention.

An electroluminescent display device according to the present invention includes: a display panel having a display region and a non-display region defined therein, the display region having a light emitting region and a non-light emitting region; A cover substrate above the display panel; Wherein the external light shielding layer comprises a first layer having a first refractive index and a second layer having a second refractive index smaller than the first refractive index, The blocking layer has first and second patterns formed by the interface of the first and second layers, the first pattern corresponds to the light emitting region, and the second pattern corresponds to the non-light emitting region.

The second layer is positioned between the first layer and the display panel.

The first pattern has a curvature at a vertex, and the second pattern has a vertex at a vertex.

The cover substrate has a third refractive index, and the third refractive index is smaller than the first refractive index.

The third refractive index is larger than the second refractive index.

On the other hand, the second layer may include a plurality of particles having a fourth refractive index.

The difference between the second refractive index and the fourth refractive index is preferably 0.1 or less.

The second pattern of the external light blocking layer may correspond to the non-display region.

And an adhesive layer between the external light shielding layer and the display panel, wherein the adhesive layer may include light absorbing particles.

Hereinafter, an electroluminescent display device according to an embodiment of the present invention will be described in detail with reference to the drawings.

2 is a schematic cross-sectional view of an electroluminescent display device according to an embodiment of the present invention.

2, the electroluminescent display device according to the embodiment of the present invention has a display area AA in which an image is displayed and a non-display area NAA surrounding the display area AA, (NAA) becomes a bezel region.

The electroluminescent display of the present invention includes a display panel 100, a cover substrate 210, an external light blocking layer 220, an adhesive layer 230, and a low reflective layer 240.

The display panel 100 realizes an image. To this end, the display panel 100 includes a plurality of pixels in the display area AA. One pixel includes red, green, and blue sub-pixels, and the pixel region corresponding to each sub-pixel may have the configuration shown in FIG. 3 is a circuit diagram showing one pixel region of a display panel according to an embodiment of the present invention.

3, the display panel 100 of the electroluminescence display device of the present invention includes a gate line GL and a data line DL that define a pixel region P and intersect with each other, A switching thin film transistor Ts, a driving thin film transistor Td, a storage capacitor Cst, and a light emitting diode D are formed in the pixel region P.

More specifically, the gate electrode of the switching thin film transistor Ts is connected to the gate wiring GL and the source electrode thereof is connected to the data wiring DL. The gate electrode of the driving thin film transistor Td is connected to the drain electrode of the switching thin film transistor Ts, and the source electrode thereof is connected to the high potential voltage VDD. The anode of the light emitting diode D is connected to the drain electrode of the driving thin film transistor Td and the cathode is connected to the low potential voltage VSS. The storage capacitor Cst is connected to the gate electrode and the drain electrode of the driving thin film transistor Td.

In the image display operation of the electroluminescence display device, the switching thin film transistor Ts is turned on according to a gate signal applied through the gate line GL, and at this time, An applied data signal is applied to the gate electrode of the driving thin film transistor Td and one electrode of the storage capacitor Cst through the switching thin film transistor Ts.

The driving thin film transistor Td is turned on according to the data signal to control the current flowing through the light emitting diode D to display an image. The light emitting diode D emits light by a current of a high potential voltage (VDD) transmitted through the driving thin film transistor Td.

That is, since the amount of current flowing through the light emitting diode D is proportional to the size of the data signal and the intensity of light emitted by the light emitting diode D is proportional to the amount of current flowing through the light emitting diode D, P) display different gradations according to the size of the data signal, and as a result, the electroluminescence display device displays an image.

The storage capacitor Cst holds the charge corresponding to the data signal for one frame to keep the amount of current flowing through the light emitting diode D constant and to keep the gradation displayed by the light emitting diode D constant .

In addition, other thin film transistors and capacitors may be added to the pixel region P in addition to the switching and driving thin film transistors Ts and Td and the storage capacitor Cst.

Referring again to FIG. 2, the cover substrate 210 is positioned on the display panel 100, that is, on the front side of the display panel 100 from which an image is output. The cover substrate 210 may be made of glass or plastic.

An external light blocking layer 220 is formed under the cover substrate 210. The external light shielding layer 220 is formed on the first surface of the cover substrate 210 facing the display panel 100 so that the external light shielding layer 220 is positioned between the display panel 100 and the cover substrate 210 do.

The external light shielding layer 220 includes a first layer 222 and a second layer 224. The second layer 224 has a lower refractive index than the first layer 222 and is located between the first layer 222 and the display panel 100.

The outer light blocking layer 220 has first and second patterns 226 and 228 that are implemented by the interface between the first layer 222 and the second layer 224. Here, the first pattern 226 and the second pattern 228 are disposed in the display area AA. At this time, the first pattern 226 in the display area AA corresponds to the light emitting area, and the second pattern 228 corresponds to the non-light emitting area, which will be described in detail later. On the other hand, only the second pattern 228 is disposed in the non-display area NAA.

Next, an adhesive layer 230 is formed under the external light shielding layer 220. That is, the adhesive layer 230 is positioned between the external light shielding layer 220 and the display panel 100, and the cover substrate 210 having the external light shielding layer 220 formed by the adhesive layer 230 is bonded to the display panel 100 Respectively. The adhesive layer 230 has an area corresponding to the external light shielding layer 220 and is located corresponding to the non-display area NAA as well as the display area AA.

On the other hand, a low reflective layer 240 having a relatively low reflectance may be formed on the cover substrate 210. That is, the low reflection layer 240 may be formed on the second surface of the cover substrate 210 opposite to the display panel 100.

As described above, the electroluminescent display device of the present invention includes the external light blocking layer 220 on the display panel 100 to prevent reflection of external light. Since the external light blocking layer 220 has different patterns corresponding to the light emitting region and the non-light emitting region in the display region AA, the efficiency of light output from the light emitting diode is increased while effectively blocking external light, The brightness of the display device can be improved.

Since the external light shielding layer 220 of the present invention has the second pattern 228 corresponding to the non-display area NAA, it is possible to prevent the black luminance from lowering in the non-display area NAA and to improve the viewing angle .

The structure of the electroluminescence display of the present invention will be described in more detail with reference to FIGS. 4 and 5. FIG.

FIG. 4 is a cross-sectional view of an electroluminescent display device according to an embodiment of the present invention, and FIG. 5 is a cross-sectional view of an external light blocking layer according to an embodiment of the present invention.

4 and 5, the display panel 100 of the electroluminescence display of the present invention includes a substrate 110, a thin film transistor T on the substrate 110, a light emitting diode D, And an encapsulation layer 180.

In more detail, a patterned semiconductor layer 122 is formed on the substrate 110. The substrate 110 may be a glass substrate or a plastic substrate. For example, polyimide may be used as the plastic substrate, but is not limited thereto. Here, a buffer layer (not shown) may be further formed between the substrate 110 and the semiconductor layer 122.

The semiconductor layer 122 may be made of an oxide semiconductor material. In this case, a light shielding pattern (not shown) may be further formed under the semiconductor layer 122, and the light shielding pattern interrupts the light incident on the semiconductor layer 122 so that the semiconductor layer 122 is deteriorated by light prevent. Alternatively, the semiconductor layer 122 may be made of polycrystalline silicon. In this case, impurities may be doped on both edges of the semiconductor layer 122.

A gate insulating layer 130 is formed on the entire surface of the substrate 110 on the semiconductor layer 122. The gate insulating layer 130 may be formed of an inorganic insulating material. When the semiconductor layer 122 is made of polycrystalline silicon, the gate insulating layer 130 may be formed of silicon oxide (SiO ₂ ). Alternatively, when the semiconductor layer 122 is made of polycrystalline silicon, the gate insulating layer 130 may be formed of silicon oxide (SiO ₂ ) or silicon nitride (SiNx).

A gate electrode 132 made of a conductive material such as metal is formed on the gate insulating layer 130 to correspond to the center of the semiconductor layer 122. A gate line (not shown) and a first capacitor electrode (not shown) may be formed on the gate insulating layer 130. At this time, the gate wiring may extend along the first direction, and the first capacitor electrode may be connected to the gate electrode 132.

Although the gate insulating layer 130 is formed on the entire surface of the substrate 110 in the exemplary embodiment of the present invention, the gate insulating layer 130 may be patterned to have the same shape as the gate electrode 132.

On the other hand, an interlayer insulating layer 140 is formed on the entire surface of the substrate 110 on the gate electrode 132. The interlayer insulating film 140 may be formed of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiN x), or an organic insulating material such as photo acryl or benzocyclobutene .

The interlayer insulating film 140 has first and second contact holes 140a and 140b that expose both upper surfaces of the semiconductor layer 122. [ The first and second contact holes 140a and 140b are spaced apart from the gate electrode 132 on both sides of the gate electrode 132. The first and second contact holes 140a and 140b are also formed in the gate insulating layer 130 formed on the entire surface of the substrate 110. [

Alternatively, when the gate insulating film 130 is patterned to have the same shape as the gate electrode 132, the first and second contact holes 140a and 140b are formed only in the interlayer insulating film 140. [

On the interlayer insulating layer 140, source and drain electrodes 142 and 144 are formed of a conductive material such as a metal. A data line (not shown), a power supply line (not shown), and a second capacitor electrode (not shown) may be formed on the interlayer insulating layer 140 in the second direction.

The source and drain electrodes 142 and 144 are spaced around the gate electrode 132 and contact the two sides of the semiconductor layer 122 through the first and second contact holes 140a and 140b, respectively. Although not shown, the data wiring extends along the second direction and crosses the gate wiring to define each pixel region, and the power wiring for supplying the high potential voltage is located apart from the data wiring. The second capacitor electrode is connected to the drain electrode 144, and overlaps the first capacitor electrode to form a storage capacitor with the dielectric interlayer 140 between the two.

On the other hand, the semiconductor layer 122, the gate electrode 132, and the source and drain electrodes 142 and 144 constitute a thin film transistor T. The thin film transistor T has a coplanar structure in which the gate electrode 132 and the source and drain electrodes 142 and 144 are located on one side of the semiconductor layer 122, .

Alternatively, the thin film transistor T may have an inverted staggered structure in which a gate electrode is located below the semiconductor layer and source and drain electrodes are located above the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

Here, the thin film transistor T corresponds to a driving thin film transistor of an electroluminescence display, and a switching thin film transistor (not shown) having the same structure as the driving thin film transistor T corresponds to each pixel region, As shown in FIG. At this time, the gate electrode 132 of the driving thin film transistor T is connected to the drain electrode (not shown) of the switching thin film transistor T and the source electrode 142 of the driving thin film transistor T is connected to the power supply wiring . In addition, a gate electrode (not shown) and a source electrode (not shown) of the switching thin film transistor are connected to the gate wiring and the data wiring, respectively.

A first insulating layer 152 and a second insulating layer 154 are sequentially formed on the entire surface of the substrate 110 as insulating materials on the source and drain electrodes 142 and 144. The first insulating layer 152 may be formed of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx), and the second insulating layer 154 may be formed of an organic insulating material such as photoacryl or benzocyclobutene And the upper surface of the second insulating film 154 may be flat.

The first insulating layer 152 and the second insulating layer 154 have a drain contact hole 156 exposing the drain electrode 144. Here, the drain contact hole 156 is formed directly on the second contact hole 140b, but may be formed apart from the second contact hole 140b.

One of the first insulating film 152 and the second insulating film 154 may be omitted. For example, the first insulating layer 152 made of an inorganic insulating material may be omitted, but the present invention is not limited thereto.

The first electrode 160 is formed of a conductive material having a relatively high work function on the second insulating layer 154. The first electrode 160 is formed in each pixel region and contacts the drain electrode 144 through the drain contact hole 156. For example, the first electrode 160 may be formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

The electroluminescent display device of the present invention may be a top emission type, and a reflective electrode or a reflective layer formed of a metal material having high reflectance may be further formed under the first electrode 160. For example, the reflective electrode or reflective layer may comprise an aluminum-palladium-copper (APC) alloy or silver (Ag). At this time, the first electrode 160 may have a triple-layer structure of ITO / APC / ITO or ITO / Ag / ITO, but is not limited thereto.

A bank layer 162 is formed on the first electrode 160 as an insulating material. The bank layer 162 may be made of an organic insulating material having a hydrophobic property.

The bank layer 162 covers the edge of the first electrode 160 and has a through hole exposing the first electrode 160. The portion corresponding to the transmission hole of the bank layer 162, that is, the portion surrounded by the bank layer 162 becomes the light emitting region A1 and the portion corresponding to the bank layer 162 becomes the non-light emitting region A2 .

Here, although the bank layer 162 is shown as having a single layer structure, it is not limited thereto. In one example, the bank layer may have a bilayer structure. That is, the bank layer includes the first bank and the second bank above the first bank, and the width of the first bank may be wider than the width of the second bank. In this case, the first bank may be formed of an inorganic insulating material or an organic insulating material having a hydrophilic property, and the second bank may be formed of an organic insulating material having a hydrophobic property.

A light emitting layer 164 is formed on the first electrode 160 exposed through the transmission hole of the bank layer 162. Although not shown, the light emitting layer 164 includes a hole auxiliary layer, a light-emitting material layer, and an electron auxiliary layer sequentially disposed from the top of the first electrode 160 . The light emitting material layer may be formed of an organic light emitting material such as a phosphorescent compound or a fluorescent compound, or may be formed of an inorganic light emitting material such as a quantum dot.

Here, the hole-assist layer, the light-emitting material layer, and the electron-assist layer may be formed through a solution process. Thus, the process can be simplified and a display device with a large area and high resolution can be provided. As the solution process, a spin coating method, an inkjet printing method, or a screen printing method may be used.

Alternatively, the hole-assist layer, the light-emitting material layer, and the electron-assist layer may be formed through vacuum deposition.

Alternatively, the hole-assist layer, the light-emitting material layer and the electron-assist layer may be formed by a combination of a solution process and a vacuum deposition.

The hole assist layer may include at least one of a hole injecting layer (HIL) and a hot transporting layer (HTL). The electron assist layer may include an electron injecting layer (EIL) and an electron transporting layer (ETL).

Although the light emitting layer 164 is shown only on the first electrode 160 surrounded by the bank layer 162 in the drawing, the light emitting layer 164 may be formed substantially on the entire surface of the substrate 110. That is, the light emitting layer 164 may also be formed on the upper surface and the side surface of the bank layer 162.

A second electrode 166 made of a conductive material having a relatively low work function is formed on the entire surface of the substrate 110 above the light emitting layer 164. Here, the second electrode 166 may be formed of aluminum, magnesium, silver, or an alloy thereof, but is not limited thereto.

The first electrode 160, the light emitting layer 164 and the second electrode 166 constitute a light emitting diode D. The first electrode 160 serves as an anode and the second electrode 166 serves as an anode. And serves as a cathode.

As described above, the electroluminescent display device of the present invention may be a top emission type in which light from the light emitting layer 164 is output to the outside through the second electrode 166, and the second electrode 166 may have a relatively thin thickness so that light is transmitted.

At this time, the light emitting diode D may have a thickness corresponding to the micro-cavity effect. Thus, the light efficiency can be increased.

An encapsulation layer 180 is formed on the second electrode 166. The encapsulation layer 180 protects the light-emitting diode D by blocking water or oxygen that flows in from the outside.

The encapsulation layer 180 is made of a photocurable or thermosetting material and may include a moisture absorbent. Alternatively, the encapsulation layer 180 may comprise at least one inorganic insulating layer and at least one organic insulating layer. For example, the encapsulation layer 180 may have a laminated structure of a first inorganic insulating layer, an organic insulating layer, and a second inorganic insulating layer, but the present invention is not limited thereto.

On the other hand, the cover substrate 210 is positioned on the display panel 100, that is, on the encapsulation layer 180. The cover substrate 210 may be a glass substrate or a plastic substrate. For example, the plastic substrate may be transparent polyimide, polycarbonate (PC), or polymethyl methacrylate (PMMA), but is not limited thereto.

The external light blocking layer 220 is formed on the first surface of the cover substrate 210 facing the encapsulation layer 180, that is, below the cover substrate 210.

The outer light blocking layer 220 includes a first layer 222 having a first refractive index and a second layer 224 having a second refractive index lower than the first refractive index. Here, the second layer 224 is located between the encapsulation layer 180 of the display panel 100 and the first layer 222.

The refractive index difference between the first layer 222 and the second layer 224 is preferably greater than or equal to 0.1 and less than or equal to 0.8. In one example, the first refractive index of the first layer 222 may be greater than or equal to 1.6 and less than or equal to 2.0, and is not limited thereto. Further, the second refractive index of the second layer 224 may be greater than or equal to 1.2 and less than or equal to 1.4, but is not limited thereto.

Meanwhile, the cover substrate 210 has a third refractive index, and the third refractive index is smaller than the first refractive index. At this time, the difference between the first refractive index and the third refractive index is preferably smaller than the difference between the first refractive index and the second refractive index. That is, the third refractive index is preferably smaller than the first refractive index and larger than the second refractive index.

For example, the third refractive index is greater than or equal to 1.4 and less than 1.6, and the difference between the first refractive index and the third refractive index may be greater than 0 and less than or equal to 0.6.

The outer light blocking layer 220 of the present invention has first and second patterns 226 and 228 which are realized by the interface between the first layer 222 and the second layer 224. Here, the first layer 222 has a recessed structure corresponding to the first and second patterns 226 and 228, and the second layer 224 has a structure corresponding to the first and second patterns 226 and 228 It has an embossed structure. For ease of explanation, the first and second patterns 226 and 228 are described with reference to the embossed structure of the second layer 224.

The first pattern 226 has a curvature corresponding to a vertex, and the second pattern 228 has a vertex angle corresponding to a vertex. The first pattern 226 may have a semicircular cross-section and the second pattern 228 may have a triangular cross-section. In one example, the first pattern 226 may be hemispherical and the second pattern 228 may be cone or polygonal, but is not limited thereto.

A plurality of first patterns 226 are located in the light emitting region A1 and a plurality of second patterns 228 are located in the non-emitting region A2. It is preferable that the number of the first patterns 226 located in the light emitting region A1 and the number of the second patterns 228 located in the non-emitting region A2 is two or more. The width of each of the first and second patterns 226 and 228 may be between 2 탆 and 20 탆.

The first and second layers 222 and 224 may be formed by a method such as coating. For example, the first and second layers 222 and 224 may be made of a polymer material or an organic hybrid material, but the present invention is not limited thereto.

Meanwhile, as shown in FIG. 5, the second layer 224 may include a plurality of first particles 224a. The first particles 224a may be contained in an amount of 5 wt% to 50 wt%.

The refractive index of the first particles 224a is preferably 1.4 or less. At this time, the difference between the refractive index of the first particle 224a and the second refractive index of the second layer 224 is preferably 0.1 or less. If the difference between the refractive index of the first particle 224a and the second refractive index is greater than 0.1, the haze becomes large and the transmittance becomes low.

The first particles 224a may be, but not limited to, fused silica, hollow silica, metal fluoride, and the like. Here, the hollow silica may adjust the refractive index along the void ratio therein, and the porosity of the hollow silica is preferably 50% or less. The metal fluoride may be NaF or MgF ₂ .

The size of such first particles 224a is greater than or equal to 1 nm and less than or equal to 300 nm. If the size of the first particles 224a is larger than 300 nm, aggregation occurs between the first particles 224a and the haze becomes very high, so that the transmittance is lowered. The size of the first particles 224a may preferably be 200 nm or less.

Next, an adhesive layer 230 is formed under the external light shielding layer 220. That is, the adhesive layer 230 is positioned between the external light shielding layer 220 and the encapsulation layer 180, and the external light shielding layer 220 formed on the cover substrate 210 is encapsulated in the display panel 100, Layer 180 as shown in FIG.

This adhesive layer 230 may comprise a plurality of second particles (not shown). The second particle is made of a material that absorbs light, and may be made of carbon black, titanium black, or metal black. For example, titanium black may be titanium oxide, and the metal black may be a combination of silver (Ag) and tin (Sn), but is not limited thereto.

On the other hand, a low reflective layer 240 having a relatively low reflectance may be formed on the cover substrate 210. At this time, it is preferable that the low reflection layer 240 has a reflectance of 0.1 to 1.0%.

The low reflection layer 240 may be formed by coating a fluoro-silane or a metal fluoride. For example, the metal fluoride may be NaF or MgF ₂ , but is not limited thereto.

FIG. 6 is a view schematically showing a path of external light to the external light shielding layer of the present invention, and FIG. 7 is a view schematically showing a path of internal light to the external light shielding layer of the present invention.

6, a part of the external light incident on the external light blocking layer 220 of the present invention may be partially or entirely covered with the first or second layer 222 or 224 by the first or second pattern 226 or 228, And is totally reflected again at the interface between the first layer 222 and the cover substrate 210 (FIG. 4). The total reflection is repeated in the first layer 222 and then disappears.

A part of the external light incident on the external light blocking layer 220 of the present invention is refracted by the first or second pattern 226 or 228 and enters the second layer 224, The light is scattered by the first particles 224a in the external light blocking layer 220 and then disappears or is incident on the adhesive layer 230 and is absorbed by the second particles (not shown) in the adhesive layer 230.

Therefore, the external light can not be incident on the display panel (100 in Fig. 4), and reflection by external light can be prevented.

At this time, the second pattern 228 having a vertex has a larger total reflection effect than the first pattern 226 having a curvature. Accordingly, the external light blocking layer 220 of the present invention has vertexes in the non- The reflection of the external light can be further prevented.

Next, as shown in Fig. 7, part of the light incident on the external light shielding layer 220 from the light emitting diode (D in Fig. 4) of the display panel (100 in Fig. 4) The light is refracted in the front direction at the interface between the first and second layers 222 and 224 by the patterns 226 and 228 and is then incident on the cover substrate 210 in FIG. 4 through the first layer 222. Since the refractive index difference between the first layer 222 and the cover substrate 210 (FIG. 4) is relatively small, total reflection is minimized at the interface between the first layer 222 and the cover substrate 210 (FIG. 4). Therefore, the light is output to the outside through the cover substrate (210 in Fig. 4).

In this case, the first pattern 226 having a curvature can improve the front luminance as compared with the second pattern 228 having a vertex. Thus, the external light blocking layer 220 of the present invention is formed in the light emitting region A1 By providing the first pattern 226 having a curvature, the transmittance at the front face can be further increased.

Here, the light may be refracted at the interface of the first and second layers 222, 224 after being scattered by the first particles 224a. Therefore, light incident at the oblique angle with the external light blocking layer 220 can be output in the front face direction, so that the efficiency of light can be increased and the front luminance can be further improved.

Since the external light blocking layer 220 of the present invention has the second pattern 228 corresponding to the non-emitting region A2, the light incident on the non-emitting region A2 can also be output in the front face direction. Thus, the front luminance can be further increased.

On the other hand, some of the light emitted from the light emitting diode (D in Fig. 4) of the display panel (100 in Fig. 4) of the present invention can be absorbed by the second particles of the adhesive layer 230, It is possible to increase the efficiency of light compared with the conventional art.

As described above, in the electroluminescent display device of the present invention, the external light shielding layer 220 has a different pattern in the light emitting region A1 and the non-light emitting region A2, (D in FIG. 4) can be improved.

In addition, since the second layer 224 of the external light blocking layer 220 includes the first particles 224a having a relatively low refractive index, the efficiency of light emitted from the light emitting diode (D in FIG. 4) .

Since the external light blocking layer 220 is formed by coating or the like, the electroluminescent display device of the present invention can reduce the lamination process, thereby simplifying the manufacturing process and reducing the cost.

Hereinafter, the front luminance of an electroluminescent display device according to an embodiment of the present invention and an electroluminescent display device according to a comparative example will be compared. At this time, the front luminance corresponds to the difference between the luminance in the black state and the luminance in the white state in the front direction.

5), and the external light shielding layer (220 in FIG. 5) is formed in the light emitting region (A1 in FIG. 5) (226 in Fig. 5) having a corresponding vertex angle, and a second pattern (228 in Fig. 5) having a curvature corresponding to the non-luminescent region (A2 in Fig. 5).

On the other hand, the electroluminescent display device according to Comparative Example 1 does not include the external light shielding layer, and the electroluminescent display device according to Comparative Examples 2 to 4 includes the external light shielding layer. In this case, the external light blocking layer of Comparative Example 2 includes a second pattern having a vertex angle corresponding to the light emitting region and the non-emitting region, and the external light blocking layer of Comparative Example 3 includes a light emitting region and a non- 1, and the external light blocking layer of Comparative Example 4 includes a first pattern having a curvature corresponding to the light emitting region, and does not include a pattern corresponding to the non-emitting region.

Based on the front luminance of Comparative Example 1 which does not include the external light blocking layer, the electroluminescence display according to the embodiment of the present invention has a front luminance increased by about 20%. On the other hand, Comparative Example 2 has a front luminance increased by about 5%, Comparative Example 3 has a front luminance increased by about 15%, and Comparative Example 4 has a front luminance increased by about 10%.

In addition, when the alignment of the first and / or second pattern is shifted by about 10%, the electroluminescent display device according to the embodiment of the present invention has a front brightness that is about 15 to 20% higher than that of the first comparative example. On the other hand, Comparative Example 2 has a front luminance increased by about 5%, Comparative Example 3 has a front luminance increased by about 15%, and Comparative Example 4 has a front luminance increased by about 5 to 10%.

As described above, the electroluminescent display device of the present invention has different patterns (226 and 228 in FIG. 5) in the light emitting region (A1 in FIG. 5) Which is higher than that of the first embodiment.

In the electroluminescent display device of the present invention, even if the alignment of the pattern (226, 228 in Fig. 5) with respect to the emission region (A1 in Fig. 5) and the non-emission region Almost none can be seen.

8 is a plan view schematically illustrating a pixel structure of an electroluminescent display device according to an embodiment of the present invention.

8, the electroluminescent display of the present invention includes a plurality of pixels PX, and each pixel PX includes red, green, and blue sub-pixels R, G, and B. FIG. Emitting region A2 of the red, green, and blue sub-pixels R, G, and B is surrounded by the non-emitting region A2. As described above, (226 in FIG. 5) corresponding to the light emitting region A1 and has a second pattern (228 in FIG. 5) corresponding to the non-emitting region A2.

Here, the red and green subpixels R and G are symmetrically arranged in the vertical direction, and the blue subpixel B is disposed on the left or right of the red and green subpixels R and G. At this time, the blue sub-pixel B has a larger area than the red and green sub-pixels R and G. [

The blue sub-pixel B may have a rhombic shape, and the red and green sub-pixels R and G become narrower as they approach each other.

An electroluminescent display device having such a pixel (PX) structure can improve the viewing angle. However, the pixel (PX) structure of the present invention is not limited thereto.

Each of the red, green and blue sub-pixels R, G and B has a rectangular shape. The red and green sub-pixels R and G are symmetrically arranged in the vertical direction. May be disposed on the left side or the right side of the red and green sub-pixels R, G. At this time, the areas of red, green, and blue sub-pixels R, G, and B may be the same or different from each other.

Alternatively, the red, green, and blue subpixels R, G, and B may have a rectangular shape, and the red, green, and blue subpixels R, G, and B may be sequentially arranged along one direction. At this time, the areas of red, green, and blue sub-pixels R, G, and B may be the same or different from each other.

Meanwhile, although the first pattern (226 in FIG. 5) has been described as having a semi-circular cross-section in the foregoing embodiment, the cross-section of the first pattern may have another shape.

9 is a cross-sectional view schematically showing another example of the first pattern of the external light blocking layer according to the embodiment of the present invention.

9, the first pattern 226 of the outer light blocking layer of the present invention includes a first portion 226a of a lower portion and a second portion 226b of an upper portion, and the first portion 226a of the outer light- And the second portion 226b may have a curved side surface.

Here, the first portion 226a may be a truncated cone or polygonal pyramid, and the second portion 226b may be a portion of a sphere, but is not limited thereto.

The first pattern 226 having such a shape can increase the efficiency of light compared to the first pattern 226 having a semicircular cross section (FIG. 5).

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined in the appended claims. And changes may be made without departing from the spirit and scope of the invention.

100: display panel 210: cover substrate
220: external light blocking layer 222: first layer
224: second layer 226: first pattern
228: second pattern 230: adhesive layer
240: low reflective layer AA: display area
NAA: non-display area

Claims (9)

A display panel in which a display area and a non-display area are defined, the display area having a light emitting area and a non-light emitting area;
A cover substrate above the display panel;
A light shielding layer between the cover substrate and the display panel,
/ RTI >
Wherein the external light blocking layer includes a first layer having a first refractive index and a second layer having a second refractive index smaller than the first refractive index,
Wherein the external light blocking layer has first and second patterns formed by an interface between the first and second layers, the first pattern corresponds to the light emitting region, and the second pattern corresponds to the non-light emitting region Emitting device.
The method according to claim 1,
And the second layer is positioned between the first layer and the display panel.
The method according to claim 1,
Wherein the first pattern has a curvature at a vertex and the second pattern has a vertex at a vertex.
The method according to claim 1,
Wherein the cover substrate has a third refractive index, and the third refractive index is smaller than the first refractive index.
5. The method of claim 4,
And the third refractive index is larger than the second refractive index.
The method according to claim 1,
And the second layer includes a plurality of particles having a third refractive index.
The method according to claim 6,
And the difference between the second refractive index and the third refractive index is 0.1 or less.
The method according to claim 1,
And the second pattern of the external light blocking layer corresponds to the non-display area.
9. The method according to any one of claims 1 to 8,
And an adhesive layer between the external light shielding layer and the display panel, wherein the adhesive layer comprises light absorbing particles.

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